Cardiopulmonary Auscultation

Where to listen on left side?

Where to listen on right side?

Where to listen?

Left Side

MA

P

Right Side

TA

How do you listen to lungs?

Examine the respiratory movements to ensure that there are no abnormalities.

Measure the respiratory rate of the dog (number of breaths over 15 seconds X 4). Normal respiration rate for a dog is 10-30 respirations/minute.

Auscultate the tracheal bifurcation at the level of the mid-thorax (8th intercostal space). Ensure the mouth is closed to prevent panting sounds.

Auscultate sounds of the thorax dorsally, ventrally, cranioventral, craniodorsal and caudodorsally, as well as the trachea and larynx.

By auscultating the upper and lower respiratory tract, the abnormal breath sounds can be localised.

Resting Heart and Breathing Rates

Species Beats/min Breaths/minHuman 60-100 12-20Dog 70–120 10-30Cat 120–140 16-40Horse 28–40 10–14Dairy Cow 48–84 26-50Sheep 70–80 16–34Pig 70–120 32–58Ferret 180-250 33-36Rabbit 120-150 30-60Guinea Pig 200–300 42-105Mouse 450–750 80-230

*Always evaluate by rate, character and position for both cardio and respiratory auscultation!

Heart Abnormalities

Atrial fibrillation - rapid and irregular beat

Mitral regurgitation - whoosh sound caused by backward flow of blood through faulty mitral valve

Mitral valve click - sharp whoosh sound caused by a prolapsed mitral valve being pulled back suddenly by the chordae tendineae

Patent Ductus Arteriosus (PDA) – constant whoosh sound caused by blood from a persistent fetal blood vessel moving blood from the aorta to pulmonary artery

Pulmonic stenosis - extra sound caused by obstruction of flow from the right ventricle of the heart to the pulmonary artery

Subaortic stenosis (SAS) - whoosh sound caused by the flow of blood from the left ventricle being restricted under the aortic valve

Ventricular Septal Defect (VSD) – whoosh on second heart sound caused by turbulent flow into the left ventricle from the left atrium

Respiratory Abnormalities

Wheeze – course whistling sound that varies in pitch and caused by narrowing of airway anywhere from the trachea to lungs.

Monophonic wheeze – same as above, but the sound has the same pitch when breathing in and out

Pleural friction rub- clicking sound caused by layers of the inflamed pleural membrane rubbing against each other

Stridor - a high pitched vibrating noise caused by obstruction of the trachea or larynx

Stertor - heavy snoring or gasping heard on inspiration

Crackles – popping or crackling sounds heard on inspiration caused by a buildup of fluid, mucus or pus in the small airways

Pulmonary edema – gurgling or crackling sound heard at the end of inspiration caused by fluid accumulation in the tissue and air spaces of the lungs

The Stethoscope

Stem

Chest piece (diaphragm)

Flexible tubing

Binaural piece (Ear tubing)

Earpiece

Earpiece Placement